Thanks @red_menace. Hadn't been able to find the AXMenuItemCmdGlyph or a good description for the other two attributes so thank you very much for that.
I understand the basic concept of needing a recursive loop to propagate the menu tree, I'm just struggling to write it in AppleScript (my exp is in tsql, vbs and java - although the latter was a while ago now). Any chance you could help with the basic structure (or point me to a decent tutorial site)?